stinson



June 28, 1955 w. J. STINSON 2,712,117

FLASH BULB socxm;

Filed Sept. 11, 1953 ATTORNEY WV United States Patent FLASH BULB SOCKET William J. Stinson, Rochester, N. Y., assignor to Graflex, Inc., Rochester, N. Y., a corporation of Delaware Application September 11, 1953, Serial No. 379,541

2 Claims. (Cl. 339-45) The present invention relates to sockets for electric lamp bulbs and more particularly to sockets for holding photographic flashlight bulbs in a flash gun.

The primary object of the present invention is to provide an electric bulb socket which will permit of securing the bulb in the socket simply by pressing it into the socket, without turning it in or screwing it into the socket, and which will permit the bulb to be pulled from the socket withoutany turning or screwing movement.

The ordinary electric light bulb has a threaded. base which is adapted to be threaded into the bulb socket.

Because it is desirable to put a flashlight bulb in its socket as quickly as possible, it has been the practice to make flashlight bulbs with diametrically-opposite pins, and to provide two bayonet slots in the socket, for the pins so that the bulb can be secured in its socket simply by aligning the pins with the slots, pushing the bulb in the socket and turning it. It is required, however, to align the pins of the flash bulb with the axial portions of the bayonet slots before the bulb can be inserted in the socket; and this takes time, a critical item always with photographers.

The primary object of the present invention is to pro vide a bulb socket structure which will permit of putting a lamp bulb into or removing it from a socket faster than can be done with conventional socket and bulb structure.

Another object of the invention is to provide a lamp bulb socket which is inexpensive and which will hold pintype flash bulbs in a flash gun socket without requiring orientation of the pins with the socket before insertion.

A further object of the invention is to provide a lamp bulb socket, particularly for the type of bulbs used in flash lamps, which will permit of positioning the bulb in the socket simply by pressing it into the socket, and which will permit of removing the bulb from the socket simply by pushing or pulling on the bulb.

Still another object of the invention is to provide a lamp bulb socket having the advantages described and suitable for holding a conventional flashlight bulb without any modification in the bulb structure.

Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims.

In the drawing:

Fig. l is a fragmentary side elevation of a flash gun equipped with a bulb socket made according to one embodiment of this invention;

Fig. 2 is a fragmentary section on an enlarged scale showing details of the construction of the bulb socket and the reflector mounting of this gun;

Fig. 3 is a section on a somewhat enlarged scale taken on the line 33 of Fig. 2 looking in the direction of the arrows; and

Fig. 4 is a section on a much enlarged scale taken on the line 4-4 of Fig. 3 looking in the direction of the arrows.

Referring now to the drawing by numerals of reference, denotes the battery casing of the flash gun. This may be of conventional construction. Secured to the casing 10 is a head 11. This head is formed with a chamher 12 in which is mounted the tube 14 that supports the reflector 15 for the flash bulb. The reflector is of conventional construction. It may be secured to the tube 14 in any suitable manner. As shown, the tube 14 is swaged outwardly to form a shoulder 16; and the reflector 15 is held against this shoulder by spinning over the outer end of the tube. The tube extends in a direction at right angles to the axis of the casing 10. The tube 14 is adapted to be secured in the chamber 12 by a conventional arcuate clamp 17 and a clamping screw 18, which is provided with a knurled head for manipulation, and which threads into the clamp 17 through a hole 19 in the top of the head 11.

Mounted coaxially within the tube 14 is a tube 25 This tube is made of electrical conducting material, such as copper, and is of thin section so that it can readily be distorted. The tube 25 is formed intermediate its ends with an internal conical seating portion 26, and forward of this conical seating portion it is of reduced diameter as compared with its diameter rearwardly of this conical seating portion. A V

The portion 2'7 of the tube 25 forward of the conical seating portion 26 constitutes the bulb-receiving socket. This socket is crimped inwardly at 28 to provide a strengthening shoulder and is normally circular is cross section. A conventional flash bulb 30 with diametrically opposite pins 3i. may be mounted in this socket simply by shoving the bulb in the socket without orienting the pins of the bulb or turning the bulb in any way. The bulb is held in the socket 27 simply by the resilient spring grip of the thin sectioned tube on the pins 31.

The inside diameter of the socket portion 27 is slightly smaller than the measurement across the pins 31 of the flash bulb, but the inside diameter of the socket portion 27 is larger than the diameter of the body 32 of the bulb base. Insertion of the bulb base into the socket portion .27, therefore, causes the ends of the pins 31 to thrust against the Wall of the socket and to distort the springlike tube wall from a true circular shape to an elongate elliptical shape. This is illustrated diagrammatically in Fig. 4 where the original size and shape of the'socketis shown in dotted lines at 27, and the shape, to whichit is distorted by the pins 31, is shown in section in full lines at 2'7. The pins 31 thrust against the wall of the 'sgcket and elongate the tubular socket portion 27 through the axis of the pins, but the diameter of the socket portion at right angles tothe axis of the pins is shortened and approaches, but does not contact, the bulb base body 32. The normal diameter of the tubular socket portion 27 is made such that it will grip bulb bases having the smallest dimension over the pins which is allowed by manufacturing tolerances. Bulbs which run to the high limits of such manufacturing tolerances will cause a greater distortion of the bulb socket but will still enter the socket 27 because the minor diameter of the distorted tube remains larger than the body 32 of the bulb base. The pins 31 and the flash bulb itself are, therefore, held in the socket by spring grip. The lamp bulb does not have to be oriented with reference to the socket, but can be pushed in the socket at any angular position around the socket.

By varying the location of the operating area along the axis of the socket, the engagement between the pins and the socket 27 can be made operative over the full length of the socket, or at the outer end of the socket only, or at any other portion axially of the socket.

The socket is preferably made with a flared, rolled, outer end 29 for easy entry of the bulb base into the socket. The flared outer end 29 of the tube is preferably made to a diameter large enough to contact the glass bulb 30 after the base of the bulb has been seated in the socket. Thus the bulb will be held by the socket portion 27 in proper alignment with the reflector 15. The flared portion 29 might, instead of being curled over, be cut away in such manner as to leave three projecting spring prongs which would afford the centering and alignment for almost any shape of glass bulb and would allow for wide variations in pin to glass dimensions.

The crirnped portion 28 of the socket part of the tube stifiens the socket portion 27 for snap action with reference to mounting the bulb in and removing it from the socket portion 27.

The batteries in the battery case 19 serve to supply the electrical power for flashing the flash bulb. The batteries are connected to the bulb on one side of the line through a plunger 40 which is mounted in the head 11 in axial alignment with the batteries, and which is adapted to contact the upper terminal of the uppermost battery. Plunger 40 is electrically-conducting and engages an electricallyconducting plunger 42 which is mounted within the tube 25 coaxially therewith and which ex ends at right angles tothe plunger 40. The plunger 42 is reciprocablc in a retainer 43 secured in the chamber 12. This retainer is of U-shape and its right leg abuts against the right hand end-of the chamber 12. The plunger 42 has a conical insulating head or washer 44 staked to it; and it is formed with a contact button 45 which is adapted to engage at its inner end with the end terminal button 46 (Fig. 3) of the flash bulb. The plunger is held in contacting engagement with the button 46 by a coil spring 48 which is interposed between the head or washer 44 and the left leg of the retainer 43.

The batteries are connected with the flash bulb on the other side of the line through a conducting insert 50. The tube 25 is slit axially along part of its length, and the slit part is bent back upon itself as denoted at 51 to form an anchor for the inner end of a conducting screw 52 which secures the conducting insert 50 in a recess in the head 11. The conducting insert 50 is right angular in shape and has its lower end bent on itself, as denoted at 53, to form an anchor for the knurl-headed set screw 54 which serves to secure the head 11 on the battery case 10.

The plunger 42 operates as an ejector for the flash bulbs. By pressing on the right hand end of this plunger, a flash bulb can be forced out of the socket 27 against the resilient frictional holding power of the distorted socket. A flash bulb can be very easily and quickly inserted into or ejected from a socket made according to the present invention. This is of immeasurable advantage to a flash photographer who wants, or is required, to take pictures in rapid succession or on an instants notice.

While the invention has been described in connection with a particular embodiment thereof, it will be understood that it is capable of further modification, and this application is intended to cover any variations, uses, or

adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth and as fall within the scope of the invention or the limits of the appended claims.

Having thus described my invention, what I claim is:

1. A socket for an electric bulb that has diametricallyopposed, contact projections protruding laterally from the periphery of the body portion of its base and a contact disposed centrally of the bottom of said base, said socket comprising a thin, resilient, electrically-conducting, tubuat shell, which for a portion of its length is of a diameter es's than the diameter of said base measured across said lateral projections whereby said portion of said socket will be distorted and will resiliently hold said bulb when said bulb is pushed into it, and a spring-pressed contact mem ber mounted slidably in said socket axially thereof to engage said centrally-disposed contact, said spring-pressed contact; member being manually movable to eject the bulb from the socket.

2. A socket for an electric bulb that has diametricallyopposed contact projections protruding laterally beyond the periphery of the body portion of its base and that has a contact disposed centrally of the bottom of its base, said socket comprising a thin, resilient, electrically-conducting tubular shell, which at its entering end is flared outwardly to engage and center a bulb and which for a portion of its length inwardly of its entering end is of a diameter less than the diameter of said base measured across said lateral projections, whereby said portion of said socket will be distorted and will resiliently hold said bulb when said bulb is pushed into it, said shell being crimped around its periphery inwardly of said holding portion to strengthen it, a combined contact member and ejector mounted rearwardly of said crimped portion to slide axially in said shell, and a spring disposed between said combined contact member and ejector and said shell to urge said combined contact member and ejector constantly toward said entering end of said shell to cause said combined contact member and ejector to engage the centrally-disposed contact of the bulb when said bulb is in said socket, and said combined contact member and ejector being manually movable toward said entering end to eject a bulb from said socket.

References Cited in the tile of this patent UNITED STATES PATENTS 2,384,327 Mendelsohn Sept. 4, 1945 2,424,938 Lundy July 29, 1947 2,485,014 Prager Oct. 18, 1949 2,596,887 Brundage May 13, 1952 2,615,071 Schwartz et al Oct. 21, 1952 FOREIGN PATENTS 881,186 France Jan. 15, 1943 

